Tubular members, such as metallic tubes, are coupled to other tubular members or ports in devices such as valves, vehicle brakes, pumps and the like, by threaded nuts. Typically, the threaded nuts rotate with respect to the tubular members in order to establish a threaded connection without having to rotate the tubular members. Typically, a crimp, removable staple or a round wire nut is utilized on the end of tubular members.
For size 24 tubes, a captive nut is utilized instead of a wire nut and crimp nuts are not used. Consequently, a captive nut must be installed during assembly of the components prior to brazing. The brazing process causes warping of the captive nut and thread distortion. When used with size 24 tubes, crimp nuts have a tendency to flex under SAE specific torque loads resulting in fitting failures. The staple-type securing mechanism is not intended to be a permanent attachment and is not therefore not used. Wire nuts of a circular cross-section have been considered for a permanent coupling of lock nuts in this situation, but upon application of an impulse, the round wire nut may back out of the retaining groove, allowing failure of the coupling. While these difficulties arise with size 24 tube couplings, they are also a consideration with couplings for tubes of other sizes.
In view of the aforementioned considerations, there is a need for a spring lock configuration in which the lock nuts are inexpensively and reliably attached to tubular members.